(1). Field of the Invention
This invention relates to an air bag of an air bag device. The air bag device is installed for example in a door, an instrument panel, a seat or a steering wheel of a car.
(2). Description of the Prior Art
Conventionally, the air bag of an air bag device has been made by forming a base cloth, of a predetermined shape, into the shape of a bag by stitching.
Gas supplied from an inflator flows rapidly into the air bag and the air bag expands. When the air bag finishes expanding, large tensile forces act on the base cloth. For this reason, conventionally, stitching of the air bag has been carried out with extendable chain stitching in order to moderate the existing tensile forces when the air bag finishes expanding.
However, when all the stitching of the air bag is made extendable chain stitching, the problem has arisen that when a high output inflator is used in the air bag device, the gas supplied from the inflator is at a higher temperature and at a higher pressure consequently, at stitched areas of the air bag, such as in the vicinity of the inflator, there is a risk of gas leaking from between stitched portions of the base cloth thereby damaging the stitching thread.